The present invention is related to transducer-protector devices for biomedical haemodialysis Fines, of the type comprising a body of moulded plastic material having a first tubular connector of the Luer Lock female type with a conical inner surface and an outer threading, intended to be connected to a tube of a haemodialysis equipment, a second tubular connector coaxial to the first tubular connector; said first and second tubular connectors being provided with respective first and second annular radial flanges for their mutual permanent sealed connection, and a filtering membrane made of a permeable material and defining an anti-contamination sterile barrier transversally interposed between said first and second tubular connectors and having a peripheral edge clamped between said radial flanges.
Transducer-protector devices of the above-referenced type constitute essential elements in biomedical haemodialysis lines which put the dialysis equipment in connection with the patient. The primary function of the transducer element in the dialysis equipment is to continously monitor the patient's blood pressure. The protection function consists of providing a sterile barrier protecting the operators, the dialysis equipment and the patient from risks of contamination by virus-infected blood, both in liquid state and in aerosolized state, as well as to filter out any particles which might be contained in an air stream possibly fed back to the equipment for its blast cleaning.
Traditionally the body of the transducer device is made of a high resistance and high rigidity plastic material, normally polycarbonate, so as to stand sterilization operations (normally vapour and/or gamma rays sterilization or the like) before the device is put on the market. Since normally the connection between the first tubular connector and the haemodialysis equipment tube is performed through a male Luer connector made of metal (normally stainless steel) of that tube, there is the risk of a non perfectly hermetic connection, actually deriving from the high stiffness of the material of which the first tubular connector is traditionally made. As a matter of fact, even the smallest imperfection in the female and male Luer Lock coupling may result in a leakage of fluid from the connection and, therefore, in a consequent error in the measurement of the patient's blood pressure.
A solution to this problem consists of manufacturing the conical inner surface of the Luer Lock connector with a material having elasticity characteristics higher than those of the body of the device, for instance polyester or similar less rigid plastic materials, providing an insert of this material co-axially arranged within the first tubular connector and mechanically secured thereto, for instance by means of a forced fit or similar retaining systems. Such a solution has been for example proposed by the same Applicant in Italian patent application no. TO93A000368 (unpublished at the priority date of the present application).